Cartography has long been concerned with the ability to accurately portray the surface of a three-dimensional object by a planar drawing. The classical Mercatur projection, still an underlying basis of map-making today, was developed in order to render the surface of a sphere onto a planar map.
Panoramic images of a scene are two-dimensional renditions of a three-dimensional scene of up to 360.degree. in circumference. The images are synthesized by taking video footage or multiple still photographs of a scene, as the camera rotates through a range of angles. In addition, either the images individually or the synthesized image is projected onto a surface such as that of a cylinder or sphere. The surface is parametrized in terms of two coordinates, and these coordinates are uniformly sampled, so that the pixel values at the sample points can be used to generate a digital image in one of the standard image formats such as JPEG (Joint Photographics Expert Group). In this way a three-dimensional scene is rendered into a representation through a two-dimensional (planar) panoramic digital image.
Conventional panoramic digital images typically have an unnatural look to them, since the "round" 360.degree. scene is "warped" onto a single "flat" digital image. As a result, panoramic images viewed without viewer software typically have little or no utility in and of themselves. Special viewer software which corrects the perspective of the surface projection is normally necessary to view panoramic images. This software only enables a small portion (or "window") of the full panoramic image to be viewed at any single instant of time, since the perspective correction varies as the viewer's line of sight is changed.
As an example, one may consider the FLASHPIX.RTM. image format along with an extension thereof that embeds panoramic data, such as field of view and angular range information, into a FLASHPIX.RTM. image. FLASHPIX.RTM., a registered trademark of the Digital Imaging Group (DIG), is an example of a multi-resolution tiled image format. A core FLASHPIX.RTM. reader, that is not able to access the embedded panoramic data, would only be able to display the panoramic image as a flat two-dimensional image, without perspective correction. This image would appear awkward, but is nevertheless a FLASHPIX.RTM. compliant digital image that can be successfully displayed.
As another example, when a conventional panoramic image is printed, it looks like a poster with a 360.degree. view--for example, a panoramic view of New York City. However, due to warping, the details of the poster appear unnatural.